Many moons ago I attended a workshop with someone who declared himself a scholar on old Norse/Skaldic poetry. Alas, my affliction with CRS prevents me from citing the name or any published references, and I have not done sufficient study on my own to verify if what he said was correct. However one part of the discussion went something like this:

1.        Although alliteration and internal rhyme predominate, end-rhyme IS used in (at least some forms of) Skaldic verse,

2.        The first rhyme in a stanza should be perfect (i.e. sun/run) to honor the gods

3.        the second rhyme in the stanza should be imperfect (i.e. shield/heel) acknowledging that men should not be honored at the same level as the gods. (Remember that much of Skaldic verse is poems of praise about a person). This perfect/imperfect rhyme pattern is continued throughout the piece.


Comment re: the idea "perfection is impractical":
A utilitarian item is "perfect" if it fills its intended purpose without fail. Generally, you're eyes are closed when you sleep, so a blanket that keeps you warm is perfect no matter what it looks like! And a song that entertains/educates/changes mood/etc in the intended manner is perfectly written and performed.

It seems to me this notion of undeviating symmetry as a measure of perfection is an artifact of our fascination with abstractions such as mathematics. When you look at an object - ANY object - closely enough (let's say into the microscopic level, to say nothing of the atomic or sub-atomic) you will never find symmetry. Likewise in the largest scales - solar systems, galaxies, etc. The Universe (on both macro and micro scales) is a remarkably sloppy place - yet it is still perfectly itself. Maybe that's a perspective we can all keep in mind.